#include<iostream>
#include<cstring>
using namespace std;
char s[1000];
int main()
{
	
	cin >> s;
	
	for (int i=0;i<strlen(s);i++)
	{
		if (s[i]!=s[strlen(s)-1-1-i])
		{
			cout << "no" << endl;
			return 0;
		}
		if (i>=strlen(s)/2) break;
	}
	cout << "yes" << endl;
	//cout << s;
	return 0;
}



